Stopcock



Nov. 11, 1952 DyJ- VOORHORST 617,623

sToPcocx Filed Oct. 14, 1948 FIGJ 9 s n A l .v B

a ab- Q d a as 4 f 1min/fok oem; UAM voonuoner. N -Hmdmjwwvw Patented Nov. 11, `1952 STATES mruN-frlorries f v2,617,623 f l 1 i STOPCOCK Dierk Jan Voorhorst, Arnheim Netlierla'n'ds-,I asrsigno rg to J.l Stokvisy Koninklijk'eFabrek Van- Metaalwerken V.,.Ai1ihe1n, Netherlands' Application' october 14, 19,48, semina. 54,40"

the Netherlands October 18,1947

f2 claims; (01.251210'1 l /My'iinventionxrelates tot a stopcock. y The usual stopcock having a conical plughas the drawbaclcl that theplugtends` to seize or jam when-'it is heated or 4when it isrlpressed axially into its housing. Further it isdifflcult to manufacture the housing and the plug with similarly conical surfacesof sufiicient-accuracy so that the plugllias a close t in the housing. In conse-v quence ythereof it is necessary l,to grind or .lap the housingwhich" .prdeedureinvolves gher "manufacturing .costs and--inohibitsv vinterc ginglof-'the manufacturedparts.

- f 'Stop'ocksareknown in which. the engagingor contacting portipnscf the-y exterior surface of the plug and of the Vinterior' surface of the housing havetlie shape of a paIt-of'a'v sphere, said plug havin-g a cylindrical projection-enclosed in ai cylindrical recess of the housing in order to prevent any tilting movement of the plug. y

An object of the invention is to provide a stopcock in which the plug has no tendency to jam, even if the stopcock is subjected to rapid and extreme changes of temperature such asgenerally occur in conduits of central heating systems.

A further object of the invention is to provide a stopcock which is easy to manufacture with great accuracy on a lathe, thus avoiding the necessity of grinding or lapping the plug into its housing.

Stilla further object of the invention is to avoid the necessity of providing the plug with a cylindrical projection for engagement with a correspondingly shaped recess of the housing.

The invention resides in forming the portion of the plug which seats within the housing, as a body of revolution with a curved generatrix which in one vdirection continuously converges with respect to the axis of said plug, the surface of said portion of the plug being non-spherical. Preferably the generatrix has the shape of an arc of a circle;V with the center of said arc lying outside of the plug-'and disposed substantially in the radial plane passing through the large diameter end of the plug.

The stopcock according t0 the invention has the advantage that with simple tools a greater accuracy can be obtained than is possible with a conical plug engaging in a conical seat in the housing so that grinding or lapping is practically unnecessary and the plugs of different cocks are interchangeable. When manufacturing a conical plug and a conical seat in the housing, itis necessary to move the carrierl of the cutting tool along a straight line, which is very accurately main- .Lio

tained at the 4desired angle relative to thevturning axis' ofthe part being formed. turn' in'g the plug and the' Housing with'an arc'fof a as the gnratrix, 'the tool is merely swung a "utaixed ax Inthis case it is' nlyviieccsjrsary to provide a ccura-tepivot and to maintainthe' right distance" between thepointof the' tool and the aiis of'said pivot to ensure that the generating arci's automatically" and ;ec'iurate ly for-Ine n Y- y A- furtherladvantagef the stopc'c'ickv according to the invention is the possibility of using such stopcocks in conduits which arie subjected to severe or extreme changes of temperature without risking the jamming or seizing of theplug within its housing.l If' the plug .is heated'and eX-pandsfit is?A displaced` axially in the' direction away from the converging end so that any tendency to jam is prevented. In this way the cock embodying the present invention may be applied to conduits for hot liquids, gases or vapours and particularly in conduits for central heating systems. Y

Still a further advantage of the stopcock according to the invention is that wear occurs principally at the converging or small diameter end of the plug, so that the plug is always tightly sealed within its housing.

If the plug is urged axially into its housing, the pressure between the contacting surfaces of the plug and seat is greatest at the converging or small diameter end of the plug. Thus, any grease which is applied when mounting the plug, is only pressed away or squeezed from between the contacting surfaces at the small diameter end of the plug and the grease remains between those portions of the co-operating surfaces where it is necessary for maintaining a tight seal.

The drawing shows an embodiment of a stopcock according to the invention. In the drawing:

Fig. 1 is a longitudinal section of a stopco'ck:

according to the invention, and

Fig. 2 is an elevation of the plug viewed in the direction at right angles to Fig. l.

The stopcock shown in the drawing has a plug l provided with a diametrically extending bore la. At the top the plug I a square part lb is provided so that it can be turned by means of a wrench.

The plug i is seated in a housing 2 which has passages 2a and 2b for registration with the opposite ends of the bore la. One end of the housing 2 is preferably formed as a socket with an internal screw thread 2c and the other end of the housing has an external screw thread 2d for connection to suitable conduits. The outer sur- -face 4 of the plug I seats in the interior surface or seat 3 of the housing 2. The plug l is provided with a threaded stem 5 which projects from the housing and on which a nut 6 is screwed, with a washer 1 being placed between the nut 6 and the housing 2. A setu screw 8 projects radially from the plug and limits the rotation of the plug by abutting against the ends of a recess 9 in the upper edge of the housing 2.

The co-operating surfaces 4 of the plug and 3 of the housing are formed as surfaces of revolution having a generatrix which is the arc of a circle. Said arc has a radius R, the centre M of which is situated in the radial plane A-B, passing substantially through the large diameter end of the plug, and located outside of the plug body. That is, the radius R. of the generatrix is greater than the maximum diameter of the plug.

The embodiment shown in the drawing has an arc of a circle as a generatrix. However, the stopcock may also be provided with a diierently shaped curved generatrix for the co-operating surfaces 3 and 4, for example, with a curved line which has a smaller radius of curvature at the converging or small diameter end of the plug. Since a curved generatrix of this alternative form cannot be turned or produced as simply as a generatrix which is merely the arc of a circle, the embodiment shown in the drawing is ister with said passages in one position of said plug, the contacting surfaces of said plug and oi said plug seat being formed as surfaces of revolution dened by curved generatrices converging toward one end with respect to the axis of rotation of said plug, said generatrices each having the shape of an arc of a circle formed with the centerfthereof outside of said plug and substantially disposed in the radial plane passing through the large diameter end of said plug, and means urging said plug axially relative to said housing in the direction from the larger to the smaller end of said plug for seating the latter on said valve plug seat.

2. A'stopcock as set forth in claim l; wherein said urging means includes a stud extending axially from said smaller end of said plug and projecting from said housing, and securing means threaded on said stud and engageable against said housing.

DERK JAN VOORHORST.

REFERENCES CITED The following references are of record'in the file of this patent:

UNITED STATES PATENTS Germany of 1888 

